Almost two-thirds of the nations scored less than five, with Transparency International saying: "Corruption continues to plague too many countries around the world."

The Indian government is under pressure from anti-corruption campaigners to pass the new law to allow the setting up of a citizens' ombudsman, also known as the Jan Lokpal.

Leading anti-corruption campaigner Anna Hazare, who says he has the support of millions, has warned he will resume a hunger strike and revive street protests that rocked the government this year if the new law does not come into force.

Mr Hazare went on a 12-day hunger strike in August.

An alleged telecoms scam, which may have cost the country $39bn (£23bn), is only one of a number of scandals besetting the government.